Multi-proxy Signature Research Articles

Proxy-Protected Proxy Multi-Signature Based on Elliptic Curve

In this work, we propose a proxy-protected proxy multi-signature scheme based on EllipticCurve Digital Signature Algorithm (ECDSA), which aims at providing data authenticity,integrity, and non-repudiation to satisfy the basic properties of partial delegation proxy signaturedescribed by Mambo et al. as well as strong proxy signature properties defined byLee et. al. The proposed signing/verifying scheme combines the advantages of proxyprotectedsignature and multi-signature scheme. The security of the proposed schemes isbased on the difficulty of breaking the elliptic curve discrete logarithm problem (ECDLP).The scheme proposed is faster and secure than the multi-signature based on factoring ordiscrete logarithm problem (DLP). The final multi-signature of a message can be verifiedindividually for each signer or collectively for a subgroup or entire group as well. Finally,the proposed proxy-protected proxy multi-signature schemes can be used in E-commerceand E-government application, which can be implemented using low power and small processingdevices.

Certificateless proxy multi-signature

Proxy multi-signature allows a group of original signers to delegate their signing capabilities to a proxy signer in such a way that the proxy signer can sign messages on behalf of the group of original signers. Existing constructions of proxy multi-signatures are based on traditional Public Key Infrastructure or Identity-based Public Key Setting, but the former needs certificates which bring about many certificate management problems, and the latter has a drawback of key escrow. In contrast to the existing constructions, in this paper, we study proxy multi-signature in Certificateless Public Key Cryptography (CL-PKC) which combines the advantages of both certificate-based and identity-based cryptosystems as it avoids the use of certificates and does not suffer from key escrow. We provide the definition and the security model for Certificateless Proxy Multi-Signature (CLPMS), and propose the first CLPMS scheme which is proved to be secure in the random oracle model under the computational Diffie–Hellman assumption. Our scheme is computationally efficient and has the property that the size of a proxy multi-signature is independent of the number of the original signers.

Independent verification of proxy multi-signature scheme

Privacy has become one of the most important human rights of the modern age. To our knowledge, in order to verify the validity of the proxy multi-signature, the verifier needs to get all the original signers' public keys together. Obviously, the verification would leak the relationships between the proxy signer and the original signers. In this paper, we propose a special secure proxy multi-signature scheme which can be used in the scene: the proxy signer hopes to make the verifier verify the signature with only the special original signers' public keys while keeping other delegations secret. After the proxy signer finished a proxy multi-signature, others can verify it using the public keys of the special original signers, rather than collecting all the original signers' public keys. We call the scheme the independent verification of proxy multi-signature IVPMS scheme.

Cryptanalysis and Improvement of a Certificateless Multi-proxy Signature Scheme

Certificateless cryptography is a new type of public key cryptography, which removes the certificate management problem in traditional public key cryptography and the key escrow problem in identity-based public key cryptography. Multi-proxy signature is an extension of proxy signature, which allows an original signer authorizing a group of proxy signers and only the cooperation of all proxy signers in the group can create valid proxy signatures on behalf of the original signer. Recently, Jin and Wen combined certificateless cryptography with multi-proxy signature, and proposed a model as well as a concrete scheme of certificateless multi-proxy signature. They claimed that their scheme is provably secure in their security model. Unfortunately, in this paper by giving two attacks, we will show that their certificateless multi-proxy signature scheme can be broken. The first attack indicates their security model is flawed and the second attack indicates their certificateless multi-proxy signature scheme is insecure. Possible improvements are also suggested to prevent these attacks.

Cryptanalytic Performance Appraisal of Improved CCH2 Proxy Multisignature Scheme

Many of the signature schemes are proposed in which thetout ofnthreshold schemes are deployed, but they still lack the property of security. In this paper, we have discussed implementation of improved CCH1 and improved CCH2 proxy multisignature scheme based on elliptic curve cryptosystem. We have represented time complexity, space complexity, and computational overhead of improved CCH1 and CCH2 proxy multisignature schemes. We have presented cryptanalysis of improved CCH2 proxy multisignature scheme and showed that improved CCH2 scheme suffered from various attacks, that is, forgery attack and framing attack.

Independent Verification of Proxy Multi-Signature without Random Oracle

Privacy has become one of the most important human rights of the modern age. In a proxy multi-signature scheme, the verifier need get all the original signers’ public keys together to verify its validity. However, the relationships between the proxy signer and the original signers would be leaked in the verification process. In this paper, we propose a secure proxy multi-signature scheme in standard model with the property of independent verification. In the scheme, the verifier can verify the signature using the public keys of the special original signers, rather than collecting all the original signers’ public keys.

An Anonymous but Accountable Proxy Multi-signature Scheme

in a proxy multi-signature, the proxy signer can sign a message on behalf of more than one original signer. However, in some cases, the proxy or the original signers do not want to leak the proxy signer's identity. In addition, when something is wrong with the signed message , the identity of the proxy signer has to be revealed. So the problem of anonymous but accountable ha s been proposed. Using the technology of pseudonym and secret sharing, in this paper, a simple method was proposed to reach the target of anonymous but accountable. In the scheme, the identity of the proxy signer was anonymous, but when t or more original signers want to reveal the proxy signer's identity, the proxy signer’s identity would be revealed and be demonstrated.

An Intranet Connection Scheme in TNC Based on Proxy Multi-Signature

An Intranet Connection Scheme in TNC Based on Proxy Multi-Signature

Provably Secure Self-certified Multi-proxy Signature with Message Recovery

Signature schemes with message recovery based on self-certified public keys can reduce the amount of communications and computations, since the signature verification, the public key authentication and the message recovery are simultaneously carried out in a single logical step. Integrating self-certified public-key systems and the message recovery signature schemes, in 2009, Wu et al. proposed two multi-proxy signatures based on the discrete logarithms over a finite field and the elliptic curve discrete logarithms. The proxy warrant revision attacks are proposed, and it will show that Wu et al.’s schemes can not resist the proxy warrant revision attacks by either the proxy group or the original signer. Further, a formal model of self-certified multi-proxy signature and a new scheme are proposed. The proposed scheme is provably secure in the random oracle model.

Improved certificateless multi-proxy signature

Multi-proxy signature is a scheme that an original signer delegates his or her signing capability to a proxy group. In the scheme, only the cooperation of all proxy signers in the proxy group can create a signature on behalf of the original signer. Jin and Wen firstly defined the formal security model of certificateless multi-proxy signature (CLMPS) and proposed a concrete CLMPS scheme. However, their construction has three problems: the definition of the strengthened security model is inaccurate, the concrete signature scheme has a security flaw, and the proof of the security is imperfect. With further consideration, a remedial strengthened security model is redefined, and an improved scheme is also proposed, which is existentially unforgeable against adaptively chosen-warrant, chosen-message and chosen-identity attacks in the random oracles. In this condition, the computational Diffie-Hellman (CDH) assumption is used to prove full security for our CLMPS scheme.

Efficient ID-based proxy multi-signature scheme secure in random oracle

Proxy signature schemes enable an entity to delegate its signing rights to any other party, called proxy signer. As a variant of proxy signature primitive, proxymultisignature allows a group of original signers to delegate their signing capabilities to a single proxy signer in such a way that the proxy signer can sign a message on behalf of the group of original signers. We propose a concrete ID-based proxy multi-signature scheme from bilinear pairings. The proposed scheme is existential unforgeable against adaptively chosen message and given ID-attack in random oracle model under the computational Diffie-Hellman (CDH) assumption. The fascinating property of new scheme is that the size of a proxy multi-signature is independent of the number of original signers. Furthermore the proposed scheme is simple and computationally more efficient than other ID-based proxy multisignature schemes.

An ID-Based Proxy Multi-Signature Scheme

Proxy multi-signature is an extension of the basic proxy signature primitive, and permits two or more entities to delegate their signing capabilities to the same other entity. Combining proxy multi-signature with identity based cryptography, in this paper, We construct a concrete identity based proxy multi-signature scheme by using bilinear pairings. Analysis shows that the scheme is capable of resisting forgery attack and can satisfy all the required security properties of a proxy signature. Furthermore, the new scheme is very simple and efficient computationally. It has the property that the size of a proxy multi-signature is independent of the number of the original signers.

Attacks on Self-Certified Multi-Proxy Signature Schemes with Message Recovery

Signature schemes with message recovery based on self-certified public keys can reduce the amount of communications and computations, since the signature verification, the public key authentication and the message recovery are simultaneously carried out in a single logical step. Integrating self-certified public-key systems and the message recovery signature schemes, in 2009, Wu et al. proposed two multi-proxy signatures based on the discrete logarithms over a finite field and the elliptic curve discrete logarithms. The proxy warrant revision attacks are proposed, and it will show that Wu et al.’s schemes can not resist the proxy warrant revision attacks by either the proxy group or the original signer.

(t,k,n) Multi-Blind Proxy Signature Scheme on Elliptic Curve

On the elliptic curve cryptosystem proposed a new multi-proxy signature scheme - (t, k, n) threshold blind proxy signature scheme.In new program blind proxy signature and (t,k,n) threshold secret sharing scheme will be combined, and will not over-concentration of the rights of the blind proxy signer .Computation of the program is small, security is high, the achieve efficiency and the utility is better .can prevent a malicious user's forgery attack and have the security properties of proxy signature.

An Improved Proxy Multi-Signature, Multi-Proxy Signature and Multi-Proxy Multi-Signature Scheme

Zhou’s proxy multi-signature scheme was a safe and effective scheme, but this scheme was not safety enough. In this work, security analysis was given to the scheme and results showed that the scheme was very easy aggressed by the forgery attack. The paper proposed that any attacker can sign some certain unauthorized messages after the attacker knows a valid signature, and any original signer ally with his proxy signer can forge any unauthorized messages. Then, the paper gave two kinds of inside attacks and outside attacks to the scheme correspondingly. Finally this paper proposed a new improved proxy multi-signature, multi-proxy signature and multi-proxy multi-signature schemes which based on the difficulty of the discrete logarithm problem (DLP). With verifying all the signers’ public keys, the improved schemes can resist lots of outsider attack and insider attack. The validity of the new scheme can be verified, and they are secure signature schemes.

Improvement of a Forward-Secure Multi-Proxy Signature Scheme

This paper shows some insecurities in Xu’s forward secure multi-proxy signature scheme. There are two kinds of attacks on this scheme: (1) anyone can forge some certain messages which to be sign and cannot detect by the signature verifier. (2) This scheme can’t resist the dishonest signer forgery attack by forging its own public key. After that, the paper proposed two new forward-secure multi-proxy signature schemes based on discrete logarithm problem and quadratic residues. With verifying all the signers’ public keys, the improved schemes can resist lots of outsider attack and insider attack as above mentioned. The validity of the new scheme can be verified, and they are secure multi-signature schemes.

On the security of an identity based multi-proxy signature scheme

In a multi-proxy signature scheme, an original signer could authorize a proxy group as his proxy agent. Then only the cooperation of all the signers in the proxy group can generate the proxy signatures on behalf of the original signer. Recently, Cao and Cao gave the first formal definition and security model of an identity-based multi-proxy signature scheme, then proposed an identity-based multi-proxy signature scheme from bilinear pairings and proved its security in their security model. Although they proved that their scheme is secure under this model, we disprove their claim and show that their scheme is not secure. We also present a simple fix to prevent this attack.

A New ID-based Designated Verifier Proxy Multi-Signature Scheme

Proxy multi-signature allows a proxy signer to generate signatures on behalf of a group of original signers. In a designated verifier signature scheme, the signature only can be verified by a designated person. In this paper, we give the model of ID-based designated verifier proxy multi-signature and present a new ID-based designated verifier proxy multi- signature scheme. Its security is based on the computational Diffie-Hellman (CDH) problem and it is highly efficient.

Certificateless multi-proxy signature

Multi-proxy signature is a scheme that an original signer authorizes a proxy group as his proxy agent and later only the cooperation of all proxy signers in the proxy group could sign messages on behalf of the original signer. To our best knowledge, most of the existing multi-proxy signature schemes are proposed in public key infrastructure or identity-based setting. However, due to avoiding the inherent escrow problem of identity-based cryptography and yet not requiring certificates to guarantee the authenticity of public keys, certificateless public key cryptography has become an attractive paradigm on which many cryptographical primitives are based. In this paper, a generic construction and a formal security model of certificateless multi-proxy signature (CLMPS) are firstly defined. A concrete CLMPS scheme is also proposed, which is proven to be existentially unforgeable against adaptively chosen warrant attacks and chosen message and identity attacks in the random oracle model under the computational Diffie–Hellman assumption.

Provably secure multi-proxy signature scheme with revocation in the standard model

Multi-proxy signature schemes are very useful tools when an original signer needs to delegate his signing capability to a group of proxy signers, and have been suggested in numerous applications. The proxy revocation problem is an essential issue of the proxy signature schemes, however, it is seldom considered in the multi-proxy signature schemes. In this paper, we give a formal definition and security model of the multi-proxy signature schemes with proxy revocation, and propose a multi-proxy signature scheme with proxy revocation. Our scheme can perform the immediate revocation by using a security mediator (SEM), who examines whether each proxy signer signs according to a warrant or its identity exists in a revocation list, and then decides if it issues a proxy token for each proxy signer. The proposed scheme is proven existentially unforgeable against chosen message/warrant attacks based on the computational Diffie–Hellman intractability assumption in the standard model. Furthermore, the size of a multi-proxy signature is constant and independent of the number of the proxy signers.